/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.dx.dex.code;

import com.android.dx.util.FixedSizeList;

/**
 * Table of catch entries. Each entry includes a range of code addresses for
 * which it is valid and an associated {@link CatchHandlerList}.
 */
public final class CatchTable extends FixedSizeList implements
		Comparable<CatchTable> {

	/** {@code non-null;} empty instance */
	public static final CatchTable EMPTY = new CatchTable(0);

	/**
	 * Constructs an instance. All indices initially contain {@code null}.
	 * 
	 * @param size
	 *            {@code >= 0;} the size of the table
	 */
	public CatchTable(int size) {
		super(size);
	}

	/**
	 * Gets the element at the given index. It is an error to call this with the
	 * index for an element which was never set; if you do that, this will throw
	 * {@code NullPointerException}.
	 * 
	 * @param n
	 *            {@code >= 0, < size();} which index
	 * @return {@code non-null;} element at that index
	 */
	public Entry get(int n) {
		return (Entry) get0(n);
	}

	/**
	 * Sets the entry at the given index.
	 * 
	 * @param n
	 *            {@code >= 0, < size();} which index
	 * @param entry
	 *            {@code non-null;} the entry to set at {@code n}
	 */
	public void set(int n, Entry entry) {
		set0(n, entry);
	}

	/** {@inheritDoc} */
	public int compareTo(CatchTable other) {
		if (this == other) {
			// Easy out.
			return 0;
		}

		int thisSize = size();
		int otherSize = other.size();
		int checkSize = Math.min(thisSize, otherSize);

		for (int i = 0; i < checkSize; i++) {
			Entry thisEntry = get(i);
			Entry otherEntry = other.get(i);
			int compare = thisEntry.compareTo(otherEntry);
			if (compare != 0) {
				return compare;
			}
		}

		if (thisSize < otherSize) {
			return -1;
		} else if (thisSize > otherSize) {
			return 1;
		}

		return 0;
	}

	/**
	 * Entry in a catch list.
	 */
	public static class Entry implements Comparable<Entry> {

		/** {@code >= 0;} start address */
		private final int start;

		/** {@code > start;} end address (exclusive) */
		private final int end;

		/** {@code non-null;} list of catch handlers */
		private final CatchHandlerList handlers;

		/**
		 * Constructs an instance.
		 * 
		 * @param start
		 *            {@code >= 0;} start address
		 * @param end
		 *            {@code > start;} end address (exclusive)
		 * @param handlers
		 *            {@code non-null;} list of catch handlers
		 */
		public Entry(int start, int end, CatchHandlerList handlers) {
			if (start < 0) {
				throw new IllegalArgumentException("start < 0");
			}

			if (end <= start) {
				throw new IllegalArgumentException("end <= start");
			}

			if (handlers.isMutable()) {
				throw new IllegalArgumentException("handlers.isMutable()");
			}

			this.start = start;
			this.end = end;
			this.handlers = handlers;
		}

		/** {@inheritDoc} */
		@Override
		public int hashCode() {
			int hash = (start * 31) + end;
			hash = (hash * 31) + handlers.hashCode();
			return hash;
		}

		/** {@inheritDoc} */
		@Override
		public boolean equals(Object other) {
			if (other instanceof Entry) {
				return (compareTo((Entry) other) == 0);
			}

			return false;
		}

		/** {@inheritDoc} */
		public int compareTo(Entry other) {
			if (start < other.start) {
				return -1;
			} else if (start > other.start) {
				return 1;
			}

			if (end < other.end) {
				return -1;
			} else if (end > other.end) {
				return 1;
			}

			return handlers.compareTo(other.handlers);
		}

		/**
		 * Gets the start address.
		 * 
		 * @return {@code >= 0;} the start address
		 */
		public int getStart() {
			return start;
		}

		/**
		 * Gets the end address (exclusive).
		 * 
		 * @return {@code > start;} the end address (exclusive)
		 */
		public int getEnd() {
			return end;
		}

		/**
		 * Gets the handlers.
		 * 
		 * @return {@code non-null;} the handlers
		 */
		public CatchHandlerList getHandlers() {
			return handlers;
		}
	}
}
